The invention provides an image processing apparatus and method, for processing a captured or recorded image with a dimension of M×N temporarily stored in an external memory; M and N are both integers larger than 1. The image processing apparatus includes a reading module, a buffer, a first processing module, a second processing module, and a writing module. Particularly, the image processing apparatus and method of the invention is a tile-based apparatus and method, which can decrease the width of the buffer and further reduce the hardware cost.